I. Field of the Invention
This invention is directed generally to the permanent augmentation of soft tissue and, more particularly, to the treatment of urological disorders, e.g., incontinence, vesicoureteral reflux, gastric fluid reflux, etc., by endoscopic injection of compatible micro particle implants into the submucosal tissue. Since the invention is closely related to the treatment of incontinence, it will be described in detail by reference thereto.
With the exception of urinary incontinence secondary to neurogenic disorders, incontinence occurs when the resistance to urine flow has decreased excessively, i.e., urethral resistance to urine outflow, from whatever cause, has been lowered to the point when it can no longer resist increased intra-abdominal pressure. While this may seem to be an oversimplification of the problem, in general nearly all procedures developed to restore continence are designed on this basis to restore the lost resistance to urine outflow. Similarly, the present invention allows for the control of gastric fluid reflux when submucosal injections of the micro implants are made to the esophageal-gastric junction and to the gastric-pyloric junction.
To these ends, several surgical procedures and devices have heretofore been developed and tried with varying degrees of success, e.g., suspension procedures, plications, constrictive procedures and various combinations of these. Devices which have been developed primarily operate as plugs and cannot be used on a permanent basis. Electrical stimulation and biofeedback techniques have so far been demonstrated to have limited success in treatment of incontinence and gastric reflux.
II. Discussion of the Related Art
As examples of such treatments and procedures heretofore known in the art, mention may be made of a variety of prosthetic devices based on the compression of the urethra at a given point. (See, for example, "Treatment of urinary incontinence by implantable prosthetic sphincter," by Bradley and Timm, Urology, 1:252 (1973); "Treatment of post-prostatectomy urinary incontinence using a gel prostheses", by Kaufman, Brit. J. Urol., 45:646 (1973) and "Treatment of post-prostatectomy urinary incontinence using a silicon gel prostheses", Brit. J. Urol., 48:646 (1973).
In the practice of plastic and reconstructive surgery, inert materials have frequently been implanted to fill in defects or augment weakened tissue. These have been fabricated of a variety of materials and have been implanted using several techniques.
Certain very small particle species compounded in a lubricious material have been implanted by subcutaneous injection for both soft and hard tissue augmentation. Heretofore success has been limited. Undesirable subsequent particle migration and serious granulomatous reactions have commonly resulted. This is well documented with such materials as polytetrafluoroethylene (PTFE) particles of very small diameter (&gt;90% of a diameter &lt;30 microns) in glycerine. One such product includes PTFE particles, suspended in glycerine with a minor amount of polysorbate is available under the name Polytef.RTM. (trademark of Mentor Corp. of California). This is discussed, for example, in Malizia, et al., JAMA, Volume 251, No. 24, pp. 3277-3281 (1984).
U.S. Pat. No. 4,773,393 issued Sep. 27, 1988 to Haber and Malizia and assigned to C.R. Bard, Inc. relates to an apparatus for hypodermically implanting a genitourinary prosthesis comprising an extensible, inflatable tissue expanding containment membrane to be located in the proximal periurethral tissues to add bulk to these tissues and thereby overcome urinary incontinence by means of localized, controlled tissue volume increase. In column 1, reference is made to the aforementioned JAMA article co-authored by the co-patentee Anthony A. Malizia with respect to the widespread migration of polytef particles along with granulomas. Accordingly, the patented invention is said to obviate these problems by providing a prosthesis comprising an elastomerical biocompatible containment membrane into which a biomeric fluid or suspended particulate matter such as TEFLON particles is percutaneously injected to inflate the membrane.
The use of very small diameter particulate spheres (approximately 1-20 microns) or small diameter elongated fibrils, (generally 1-20 microns in diameter) of various materials such as cross-linked collagen or synthetic polymers suspended in an aqueous medium to which a biocompatible fluid lubricant has been added as injectable implant composition is disclosed in Wallace et al., U.S. Pat. No. 4,803,075. While these materials create immediate augmentation, this result is generally short-lived as the material also has a tendency to migrate and/or be reabsorbed from the injection site by the host tissue.
Most recently, three companies have indicated in published reports their intent to enter the market for treatment of urinary incontinence with an injectable material. Mentor Corporation has received limited approval from the FDA for use of their injectable material, "Urethrin", in treating incontinent male postprostatectomy patients. Previous published reports stated that C.R. Bard, Inc. and Collagen Corporation were developing an incontinence treatment called "Contigen Bard Collagen Inplant," understood to be Collagen Corporation's "contigen" injectable bovine collagen material. Subsequently, it was reported that C.R. Bard is also evaluating for urinary incontinence treatment a product called "Hylagel-Muscle" which is said to be based upon Biomatrix's patented technology on modifying naturally occurring hyaluronan "to form three-dimensional sponge-like matrixes in the form of high molecular mass fluids, gels and solids that can separate tissue, cells and molecules."
From the foregoing survey of the current state of the art, it will thus been seen that of recent date many approaches and treatments have been proposed to cure or relieve conditions of urinary incontinence by injection. While some of these approaches have enjoyed modest success, relief has been, for the most part, only temporary in those patients where success is noted. This generally is due to granuloma reactions and/or migration of injected particulate material and reabsorption of gellular materials. Thus, there remains a very important need for a treatment that will provide a lasting remedy for successfully treating such urological disorders.